Radical-scavenging activities of citrus essential oils and their components: detection using 1,1-diphenyl-2-picrylhydrazyl

Thirty-four kinds of citrus essential oils and their components were investigated for radical-scavenging activities by the HPLC method using 1,1-diphenyl-2-picrylhydrazyl (DPPH). To examine the oils' relative radical-scavenging activities compared with that of a standard antioxidant, Trolox was employed. All of the essential oils were found to have scavenging effects on DPPH in the range of 17. 7-64.0%. The radical-scavenging activities of 31 kinds of citrus essential oils were comparable with or stronger than that of Trolox (p < 0.05). The oils of Ichang lemon (64.0%, 172.2 mg of Trolox equiv/mL), Tahiti lime (63.2%, 170.2 mg of Trolox equiv/mL), and Eureka lemon (61.8%, 166.2 mg of Trolox equiv/mL) were stronger radical scavengers than other citrus oils. Citrus volatile components such as geraniol (87.7%, 235.9 mg of Trolox equiv/mL), terpinolene (87.4%, 235.2 mg of Trolox equiv/mL), and gamma-terpinene (84.7%, 227.9 mg of Trolox equiv/mL) showed marked scavenging activities on DPPH (p < 0.05).

Clinical usefulness of urine-based enzyme-linked immunosorbent assay for detection of antibody to Helicobacter pylori: a collaborative study in nine medical institutions in Japan

BACKGROUND

A urine-based enzyme-linked immunosorbent assay (ELISA) kit for detection of antibody to Helicobacter pylori has been developed in Japan. Urine samples can be obtained noninvasively and are easier and safer to handle than are serum samples. The aim of this study was to examine the clinical usefulness of this urine-based ELISA kit.

MATERIALS AND METHODS

A pair of random, single-void urine and serum samples was collected from each of 1,061 subjects, including 238 patients with gastroduodenal disease. The sensitivity and specificity of the urine-based ELISA was compared with those of three commercially available serum-based ELISA kits. For those patients with gastroduodenal disease, the urine- and serum-based ELISA results were also compared with those for other diagnostic methods using endoscopic biopsy specimens, such as culture, histology, and rapid urease tests.

RESULTS

Based on the three serum-based ELISA results, the sensitivity, specificity, and accuracy of the urine-based ELISA were 97.7%, 95.6%, and 96.8%, respectively. On the basis of the biopsy test results, the sensitivity (96.2%), specificity (78.9%), and accuracy (91.0%) of the urine-based ELISA were almost equivalent or superior to all three serum-based ELISAs tested. In addition, 10 of the 12 false-positive cases for urine-based ELISA were confirmed to be true positives for antibodies to H. pylori by Western blot analysis and inhibition ELISA.

CONCLUSIONS

The urine-based ELISA (URINELISA H. pylori Antibody) is very accurate and should be useful as an alternative to serum-based ELISAs for screening of H. pylori infection.

Beneficial effects of fish oil on glucose metabolism in spontaneously hypertensive rats

1. Increased interest in fish oil led us to examine their metabolic effects in spontaneously hypertensive rats, which have been reported to have glucose intolerance. 2. Rats were divided into three groups: (i) a control group fed standard rat laboratory chow; (ii) a lard group fed a high-fat diet containing 20% lard; and (iii) a fish oil group fed a high-fat diet containing 20% fish oil for 14 weeks. 3. Systolic blood pressure and fasting blood glucose were markedly increased in the lard group, whereas in the fish oil group they were only transiently increased at the beginning and decreased to levels seen in the control group. 4. Intraperitoneal glucose tolerance test demonstrated that fish oil reversed the impairment of glucose disposal found in the lard group. However, plasma insulin levels were raised transiently at 30 min in the fish oil group compared with the control group. 5. Insulin secretion from pancreatic islets stimulated with glucose in vitro was also enhanced by fish oil. 6. These results lead us to conclude that fish oil improves glucose tolerance by enhancing insulin secretion from pancreatic beta-cells.

Multiple myeloma presenting high fever and high serum levels of lactic dehydrogenase, CRP, and interleukin-6

Two myeloma patients presented high fever with no signs or data indicating infection at diagnosis or relapse. Both patients had plasmablastic myeloma, and serum levels of lactic dehydrogenase (LDH) and CRP were extremely high. Plasmablastic morphology, high LDH, and CRP were recognized as poor prognostic factors, indicating a fulminant phase of multiple myeloma. Interleukin-6 (IL-6) was only high in measured cytokines. We proposed that IL-6 caused high fever and induced the fulminant phase in these 2 cases.

Relationship between the reduction of tetrazolium salt XTT and DNA strand breakage with aminosugars

Dihydropyrazine derivatives formed by the self-condensation reaction of D-glucosamine have the DNA breaking activity. To establish the monitoring method of the biological active dihydropyrazines, we investigated the relationship between the XTT (3'-[1-[(phenylamino)-carbonyl]-3, 4-tetrazolium]bis(4-methoxy-6-nitro)benzensulfonic acid hydrate) reducibility and the DNA breaking activity of aminosugars. Aminosugar in 50 mM sodium phosphate buffer (pH 7.4) was incubated at 37 degrees C. At a given time, the XTT reducibility and the DNA breaking activity of the incubated aminosugar were measured. Both XTT reducibility and DNA breaking activity showed a maximum value within 1-4 h after the incubation and then gradually decreased with the incubation time. Superoxide anion was suggested to involve in both of the DNA breaking activity and the XTT reducibility by the addition of the radical scavengers into those assay mixtures. The quantity of remaining covalently closed circular DNA and the XTT reducibility of all aminosugars showed a good correlation (r = 0.825, n = 26). This means that the XTT assay is applicable for the monitoring of those biologically active products derived from aminosugars when the participation of superoxide anion in DNA scission is recognized.

Identification of quantitative trait loci for serum cholesterol levels in stroke-prone spontaneously hypertensive rats

The stroke-prone spontaneously hypertensive rat (SHRSP) has been reported to show significantly lower levels of serum total cholesterol than the normotensive control strain Wistar-Kyoto rat (WKY). Because selective inbreeding was conducted for stroke proneness, this concomitantly inherited characteristic of SHRSP may play some pathophysiological role in stroke. We evaluated the genetic determinants of the cholesterol trait by estimating heritability and subsequently by undertaking a genome-wide screen with 161 genetic markers in F(2) progeny involving SHRSP and WKY (104 male and 106 female rats). Three quantitative trait loci (QTLs) were detected on rat chromosomes 5, 7, and 15. Markers from the linked region on chromosome 15 indicated significant evidence of linkage with a maximal log of the odds (LOD) score of 7.7, whereas those on chromosomes 5 and 7 cosegregated with the trait in a sex-specific manner (the QTL close to genetic marker D5 Mit5 reached an LOD score of 7.3 in males, and that close to D7 Mit10 reached an LOD score of 3.2 in females). The male-specific QTL on chromosome 5 appeared to overlap with previously reported QTLs for stroke-associated phenotypes, but an identical gene (or genes) appeared unlikely to control these and the cholesterol traits simultaneously. In the present study, serum cholesterol levels were shown to be highly genetically determined in SHRSP (the heritability estimates are 76% in males and 83% in females), and 3 QTLs with substantial effects were identified. Further work, however, is required to clarify whether the cholesterol trait is related to the etiology of stroke or has been retained by chance through the inbreeding process in SHRSP.

Soluble dietary fibre improves insulin sensitivity by increasing muscle GLUT-4 content in stroke-prone spontaneously hypertensive rats

1. The effects of soluble dietary fibre (psyllium) on peripheral insulin sensitivity and skeletal muscle GLUT-4 protein expression were studied in 12 male stroke-prone spontaneously hypertensive rats (SHRSP) fed a high-caloric diet from 5 to 9 weeks of age. 2. In the psyllium-supplemented group, fasting plasma glucose was significantly reduced and glucose levels following an oral glucose tolerance test were significantly lower than in the cellulose-supplemented group at 30 (P < 0.05) and 60 min (P < 0.01). However, there was no difference in insulin secretion. 3. In the psyllium-supplemented group, skeletal muscle GLUT-4 content was significantly increased in the plasma membrane (P < 0.001), but not in the intracellular membrane. 4. No significant difference was found in phosphatidylinositol 3 (PI3)-kinase activity between cellulose and psyllium diet not only in the basal state but also when stimulated by insulin. 5. These results demonstrate that psyllium increases blood glucose disposal by increasing skeletal muscle plasma membrane GLUT-4 content without PI3-kinase activation.

Inhibitory effects of citrus essential oils and their components on the formation of N-nitrosodimethylamine

Twenty-eight kinds of citrus essential oils and their components were studied for inhibitory effects on the formation of N-nitrosodimethylamine (NDMA). The reaction mixture consisted of dimethylamine and sodium nitrite adjusted at pH 3.6, in addition to essential oils and an emulsifying agent. The quantification was determined by high-performance liquid chromatography monitored at 220 nm. All of the essential oils inhibited the formation of NDMA in the range of 20-85%. The oils of ujukitsu (Citrus ujukitsu Hort. ex Shirai), yuzu (C. junos Tanaka), mochiyu (C. inflata Hort. ex Tanaka), and ponkan (C. reticulata Blanco cv. F-2426) inhibited the formation of NDMA much more effectively than other citrus oils. The inhibitory proportions of components of citrus essential oils such as myrcene, alpha-terpinene, and terpinolene were as high as 80%.

Aging and salt-loading modulate blood pressure QTLs in rats

To evaluate the effects of nongenetic factors, aging, and salt-loading on the quantitative trait loci (QTLs) for blood pressure (BP), we conducted a genome-wide linkage analysis using multiple sets of BP measurements in 125 male F2 generation cross derived from stroke-prone spontaneously hypertensive rats and normotensive Wistar-Kyoto rats. The experiment was arranged in two stages. In the first stage, corresponding to the developing period of the rats, BP was measured repeatedly without loading of salt; this continued until the rats were 5 months of age. In the second stage, after the baseline BP leveled off, 1% salt water was given to the rats and BP was monitored for the subsequent 7 months. Genome scanning was performed using 201 markers. In the developing period, three QTLs were identified on chromosomes 1, 3, and 4 (logarithmic odds [LOD] scores of 5.6, 3.1, and 3.2, respectively), which had peaks at 8 or 10 weeks of age. In the latter salt-loading stage, QTLs for BP were detected on chromosomes 1 and 10 (LOD scores 4.6 and 4.5, respectively). When the BP increase during salt-loading was analyzed as a phenotype, however, only the region on chromosome 10 showed linkage at a suggestive level (LOD score 3.2). The present study provides experimental evidence that QTLs for BP could be modulated by nongenetic factors, such as aging and salt-loading.

Analysis in spontaneously hypertensive rats

1. Linkage analysis is performed between basal or salt-sensitive high blood pressure and several loci on chromosomes in F2 progenies obtained from crossing stroke-prone spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats. 2. Basal hypertensive genes are mapped to a region near the D1Mit2 locus on chromosome 1 and near the D3Mgh8 locus on chromosome 3 in the male and female F2 progenies. 3. Salt-sensitive hypertensive gene is mapped to a region near RR1023 locus on chromosome 10 in the male F2 progenies. 4. Salt-sensitive hypertensive gene is mapped to a region near D3Mgh12 locus on chromosome 3 in the female F2 progenies.

Increased oxidative DNA damage in stroke-prone spontaneously hypertensive rats

1. The amount of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of the total systemic oxidative stress in vivo, in stroke-prone spontaneously hypertensive rats (SHRSP) was not different from that in control normotensive Wistar-Kyoto (WKY) rats at 6 weeks of age, but became higher than control values after the development of severe hypertension at 14-17 weeks of age. 2. The amount of urinary 8-OHdG was not significantly different between SHRSP treated with anti-hypertensive agents and those not treated at 14 weeks of age. 3. Stroke-prone spontaneously hypertensive rats were exposed to DNA damage by oxidative stress at the early stage when they developed severe hypertension, but this increase in DNA damage was not the secondary effect of hypertension.

Immunomodulation by vitamin B12: augmentation of CD8+ T lymphocytes and natural killer (NK) cell activity in vitamin B12-deficient patients by methyl-B12 treatment

It has been suggested that vitamin B12 (vit.B12) plays an important role in immune system regulation, but the details are still obscure. In order to examine the action of vit.B12 on cells of the human immune system, lymphocyte subpopulations and NK cell activity were evaluated in 11 patients with vit.B12 deficiency anaemia and in 13 control subjects. Decreases in the number of lymphocytes and CD8+ cells and in the proportion of CD4+ cells, an abnormally high CD4/CD8 ratio, and suppressed NK cell activity were noted in patients compared with control subjects. In all 11 patients and eight control subjects, these immune parameters were evaluated before and after methyl-B12 injection. The lymphocyte counts and number of CD8+ cells increased both in patients and in control subjects. The high CD4/CD8 ratio and suppressed NK cell activity were improved by methyl-B12 treatment. Augmentation of CD3-CD16+ cells occurred in patients after methyl-B12 treatment. In contrast, antibody-dependent cell-mediated cytotoxicity (ADCC) activity, lectin-stimulated lymphocyte blast formation, and serum levels of immunoglobulins were not changed by methyl-B12 treatment. These results indicate that vit.B12 might play an important role in cellular immunity, especially relativing to CD8+ cells and the NK cell system, which suggests effects on cytotoxic cells. We conclude that vit.B12 acts as an immunomodulator for cellular immunity.

Effects of cytosolic Ca2+ on membrane voltage and conductance of cultured mesangial cells from stroke-prone spontaneously hypertensive rats and WKY rats

Mesangial cells (MC) are considered to play an important role in the development of hypertension. The purpose of this study was to characterize the effects of cytosolic Ca2+ on membrane voltage and conductance of MC using stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar Kyoto rats (WKY). We applied the patch-clamp technique in the whole-cell configuration to measure membrane potential (Vm) and ion currents. There was no significant difference in resting Vm values between MC from WKY and SHRSP. The cytosolic Ca2+ increase induced membrane depolarization and the increase of Cl- currents in MC from WKY but not in MC from SHRSP. On the other hand, the Ca2+ increase induced membrane hyperpolarization and the increase of K+ currents in MC from SHRSP but not in MC from WKY. Such differences between MC from two rat strains may play an important role in the alterations in renal hemodynamics observed in hypertension.

A staging system for multiple myeloma based on the morphology of myeloma cells

The morphology of myeloma cells is reported to be one of the prognostic factors in multiple myeloma (MM) patients. We analyzed the prognostic factors, including morphological classification, in 292 patients with MM in order to select poor-risk patients who should be considered candidates for early intensive chemotherapy, including stem cell transplantation. Multivariate analysis was applied to 90 patients diagnosed between 1989 and 1996, because serum beta-2-microglobulin (beta2M) has been measured regularly since 1989, and showed that serum albumin, serum beta2M, and the morphology of myeloma cells predicted survival. According to these factors, patients were divided into 3 risk groups; a high-risk group (14%), a intermediate-risk group (46%) and a low-risk group (40%). There were significant differences between survival times in these 3 groups (median survival: high-risk, 16; intermediate-risk, 22; and low-risk, 44 months).

Primary nonsecretory plasma cell leukemia: a rare variant of multiple myeloma

We report a patient with primary nonsecretory plasma cell leukemia. These cells resembled prolymphocytes and expressed only CD38 and CD56. Due to the atypical morphology and lack of monoclonal immunoglobulins in both serum and urine, it was difficult to make a correct diagnosis. Electron-microscopic and immunocytochemical cytoplasmic studies were useful.

Training in swimming reduces blood pressure and increases muscle glucose transport activity as well as GLUT4 contents in stroke-prone spontaneously hypertensive rats

Exercise improves muscle insulin sensitivity and GLUT4 contents. We investigated the beneficial effects of swimming training on insulin sensitivity and genetic hypertension using stroke-prone hypertensive rats (SHRSP). We studied the relationship between genetic hypertension and insulin resistance in SHRSP and Wistar Kyoto rats (WKY) as a control. The systolic blood pressure of SHRSP was significantly reduced by 4-week swimming training (208.4 +/- 6.8 mmHg vs. 187.2 +/- 4.1 mmHg, p < 0.05). The swimming training also resulted in an approximately 20% increase in the insulin-stimulated glucose transport activity (p < 0.05) of soleus muscle strips and an approximately 3-fold increase in the plasma membrane GLUT4 protein expression (p < 0.01) in SHRSP. However, basal and insulin-stimulated glucose transport activity and GLUT4 contents were not significantly different between WKY and SHRSP. There was no difference in insulin resistance in skeletal muscle of SHRSP as compared with WKY. Our results indicated swimming training exercise improved not only hypertension but also muscle insulin sensitivity and GLUT4 protein expression in SHRSP.

Lower mevalonate pyrophosphate decarboxylase activity is caused by the reduced amount of enzyme in stroke-prone spontaneously hypertensive rat

Spontaneously hypertensive rat (stroke-prone) (SHRSP) has a low serum cholesterol level as compared with the normotensive Wistar Kyoto rat (WKY). We previously indicated that the lower activity of mevalonate pyrophosphate decarboxylase (MPD) was responsible for the reduced cholesterol biosynthesis in the liver of SHRSP [Sawamura et al. (1992) J. Biol. Chem. 267, 6051-6055]. To elucidate the mechanism of the reduced activity, we purified liver MPD from SHRSP treated with cholestyramine and pravastatin in this study. We compared its enzymatic properties with those of the enzyme from WKY, and also measured the amounts of MPD in the crude extract of various tissues in WKY and SHRSP by Western blot analysis. Results indicated that (i) MPD of SHRSP has essentially the same properties as MPD of WKY, except for a difference in the dependency on divalent cations. (ii) The amount, as well as the activity, of MPD in the crude extract of brain and liver was reduced in SHRSP. (iii) There was no difference between SHRSP and WKY, in the ratio of the enzyme activity to the amount of MPD in the crude extract. These data led us to conclude that the lower activity of MPD was caused by the reduced amount of this enzyme in SHRSP.

Genetic analysis of non-insulin-dependent diabetes mellitus in the Otsuka Long-Evans Tokushima Fatty rat

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an animal model for obese NIDDM. We performed a genome wide scan in F2 progenies obtained by crossing OLETF rats with two control strains, Long-Evans Tokushima Otsuka (LETO) and Fisher-344(F-344) rats. Since diabetes develops only in male progenies, we used only male F2 rats for the linkage studies.Highly significant linkage was observed between the phenotype, postprandial hyperglycemia and P-450ald locus on chromosome 1 and D7Mit 11 locus on chromosome 7. In addition, suggestive linkage was found between fasting glucose level and body weight and these two loci. Four other regions (D1Mit12, D2Mit11, D5Mgh14, and D17Arb1) on chromosome 1, 2, 5, and 17 were detected to influence body weight, fasting glucose level or postprandial hyperglycemia independently. We concluded that non-insulin-dependent diabetes mellitus(NIDDM) in OLETF rats is regulated by multiple genes which affect fasting, postprandial hyperglycemia, and obesity differently.

Inactivation of Cu,Zn-superoxide dismutase by intermediates of Maillard reaction and glycolytic pathway and some sugars

Human Cu,Zn-superoxide dismutase (SOD) was incubated with various intermediates of the Maillard reaction and glycolytic pathway (arabinose, glyoxal, glycolaldehyde, glyceraldehyde, glyceraldehyde 3-phosphate, and dihydroxyacetone) and some reducing sugars (sorbose, xylose, and ribose). The change of the activity and the molecular weight were measured and compared with that of SOD incubated with glucose or fructose. Sorbose, xylose, and ribose decreased the activity with a rate comparable to fructose. Site-specific and random fragmentation were observed upon the incubation with them. Arabinose showed a similar inactivation rate as glucose. The intermediates other than arabinose had a high inactivation rate. Especially, glyceraldehyde, glycolaldehyde, and glyoxal most strongly lowered the activity in a concentration-dependent manner and a significant inactivation was recognized even at 1 mM level. SDS-PAGE band patterns indicated that the inactivation by those carbonyl compounds occurred by both crosslinking and site-specific fragmentation of SOD.